ST-408N – user's manual
I. Use
ST-408N thermoregulator is intended for controlling central heating installation.
The controller supports two mixing valves, DHW pump (of water boiler), circulating
pump and a solar collector. The controller may cooperate with two ST-61 modules,
which enables the user to control the total of five mixing valves. The controller
features weather control and weekly control functions and it may support three
two-state (standard) room regulators and one TECH regulator. The device has one
voltage contact (additional contact 1) and two dry contacts (additional contacts 2
and 3). It is also compatible with GSM module and Internet module.
Return temperature protection is another asset of the device. It prevents the
water in the short circulation from boiling and ensures that the temperature of
water returning to the CH boiler is not too low.
II
.
Principle of operation
Controller operation involves mixing the hot circulating water with the water
returning from the heating circuit in order to reach and maintain the set
temperature.
Pumps which are connected to each valve circuit help to distribute the water
throughout the system. A pump should be connected behind the mixing valve
whereas the temperature sensor should be placed behind both the pump and the
valve in order to ensure accurate measurement of the valve output temperature.
Note: if the valve controller and the CH boiler controller operate simultaneously in
one circuit, the pump may be connected from the CH boiler controller (the pump
output in the ST-408N regulator and in the additional module remains unconnected)
The device is controlled using a touch screen.
II.a) Main page
During normal operation, the graphic display of the regulator shows the main
page, which may differ depending on user's settings. The main screen shows the
following information:
• current and set temperatures of the active valves,
• current and set temperature of the water boiler
• current and set temperature of the buffer
• outdoor temperature
• time and day of the week
• operation mode of the pumps
The screen view shown above is the default one in ST-408N controllers. The user
may also switch to panel screen:
-
4
-